1. Field of the Invention
The present invention relates to a semiconductor socket at a bottom of which external input and output terminals are area-arranged in a grid form such as a BGA (Ball Grid Array) used to have the semiconductor socket come into contact with probes in order to make electrical test on the semiconductor device.
2. Description of the Related Art
The semiconductor device made up of a package being called a BGA has solder balls serving as its external input and output terminals arranged at a bottom of the semiconductor device in a grid form.
In order to secure electrical characteristics of the semiconductor device as described above, a semiconductor test apparatus is used. The semiconductor test apparatus, as shown in FIG. 7, is so configured that a conventional semiconductor socket 50 is mounted in a predetermined position on a socket mounting substrate 61 constituting a socket holder 60 and in the conventional semiconductor socket 50 is housed the above semiconductor device by using a handling machine (not shown).
FIG. 4 shows the above conventional semiconductor socket 50. The conventional semiconductor socket 50 shown in FIG. 4 is provided with a stage 51 used to perform positioning on a semiconductor device at a bottom of which a plurality of solder balls is mounted, probes 53 each coming in contact with each of the solder balls placed in the semiconductor device on which positioning has been performed by approaching of the stage 51 acting against elasticity of a spring 52, a socket base 54 to house the probes 53 in an extruded state in a manner to face the socket base 54, a rear cap 55 being fixed at a bottom of the socket base 54 to prevent each of the probes 53 from coming off in a downward direction, a rear cap fixing screw 56 to fix the rear cap 55 to the socket base 54, a guide pin 58 used to guide the stage 51 so that it can come near to or can part from each of the probes 53, and a screw 57 used to fit the guide pin 58 being inserted from a side of a bottom of the socket base 54.
The stage 51 is provided with a tapering hole used to receive the semiconductor device and to perform positioning at a predetermined position. After positioning of the above semiconductor device has been performed along the tapering hole, each of the solder balls mounted in the semiconductor device is placed in an upward position of each of the probes 53. Therefore, when the stage 51, together with the semiconductor device, is pushed by an automatic machine (not shown) through the application of pressure to come near to the socket base 54, each of the solder balls mounted in the semiconductor device comes into contact with an end of the probes 53 extruding at a surface of the socket base 54. Each of the probes 53 has a contactor extruding from both ends of a circularly cylindrical body and each contactor is extendable by a coil spring in the circularly cylindrical body. The contactor being in contact with each of the solder balls is shown in FIG. 5(a) and another contactor is shown in FIG. 5(b).
In the socket holder 60 described above, as shown in FIG. 6 and FIG. 7, to a socket base 68 is fixed a socket mounting base 61 by substrate fixing screws 62. Printing wiring being in electric contact with each of the probes 53 is carried out on the socket mounting base 61 and the semiconductor socket 50 is fixed to the socket mounting base 61 using a socket fixing screw 63.
Moreover, the socket mounting base 61 is fixed on a pedestal 64 using a pedestal fixing screw 69 and the pedestal 64 is fixed on a DUT (Device Under Test) board 65 on which specified electrical circuits are formed using a board fixing screw 66. Furthermore, in order to electrically connect the socket mounting base 61 and the DUT board 65, an electrically conductive connecting pin 67 is provided between the socket mounting base 61 and the DUT board 65.
When pressure more than necessary is applied to the probes 53 and/or when force acting toward a horizontal direction is applied to the probes 53 due to an operating failure of the automatic machine pushing the stage 51 together with the semiconductor device, buckling and/or breakage occur in the contactor of each of the probes 53. In order to replace the damaged probes 53, following disassembling procedures described below are required.
First, the socket holder 60 is taken off from the automatic machine of the semiconductor test apparatus. Next, a plurality of the pedestal fixing screws 69 is removed through a hole formed in the socket base 68. Then, the socket mounting base 61 is removed from the pedestal 64. At this point, the connecting pin 67 is also removed together with the pedestal 64. Then, a plurality of substrate fixing screws 62 is removed from a bottom of the socket mounting base 61. Next, the socket mounting base 61 is removed from the socket base 68. Then, a plurality of the socket fixing screws 63 is removed from a bottom of the socket mounting base 61 and then the socket mounting base 61 is removed from the semiconductor socket 50. Next, in the semiconductor socket 50 shown in FIG. 4, a plurality of the rear cap fixing screws 56 is taken off from a bottom of the socket base 54 and then the rear cap 55 is taken off. Moreover, in order to prevent the probes 53 from falling off, the probes 53 to be replaced are pulled out by using a pincette and is replaced with a new one. After the replacement of defective probes, each member is combined using a plurality of screws in a retrograde order and the socket holder 60 described above is set to a predetermined position in the automatic machine.
Thus, since removal of the rear cap 55 existing at a bottom of the socket base 54 is necessary for the replacement of the probes 53, the semiconductor socket has to be taken off from the socket holder 60 according to the above procedures and therefore much time and efforts are required for the replacement work of the probes 53.